         true phrase))
 
 ;; TODO: warn about failures.
-(def grammar
+(defonce grammar
   (map (fn [phrase]
          (modal-is-head-feature
           (aux-is-head-feature phrase)))

    :comp {:synsem {:subcat '()}}
    :head {:synsem {:subcat '()}}}))

(def h00
  (unify-check
   head-first
   {:comment "h00"

    :schema-symbol 'h32 ;; used by over-each-parent to know where to put children.
    :first :head}))

(defonce c00
  (unify-check
   head-last
   {:comment "c00"
